Dogs may hold the reputation as having the best noses among mammals, but when it comes to the number of genes associated with smell, the elephant stands alone. By a mile. New findings published in Genome Research suggest that African elephants have 2,000 active olfactory genes, the highest number among the 13 mammals studied, giving them twice the number found in dogs and five times that found in humans. Makes sense when you consider the nature of the trunk, where "every time you touch something, you smell it," the lead scientist tells the Washington Post. But, researchers point out, the sheer number of genes doesn't mean that the elephant surpasses the dog in every way when it comes to sniffing.
Dogs, for instance, have sensitive noses that detect specific odors even at low concentrations, which explains why they're great at following the scent of a trail. Elephants, meanwhile, likely have access to a much wider range of smells—and their noses seem to be more discerning. Previous research has found that elephants can tell 30 family members apart by sniffing their urine, and that they can even differentiate between two ethnic groups in Kenya. (They fear the Maasai, who spear elephants, while they don't show the same aversion to the Kamba, who don't.) The great sense of smell likely compensates for the elephant's relatively weak vision, notes National Geographic. Interestingly, olfactory genes are extremely species-specific; of the 10,000 genes studied across the 13 species, only three were shared among all 13, reports Science. (Last month, one of the world's biggest elephants was killed.)